94 DYNAMICS OF LIVING MATTER 



already pointed out that these facts may aid us in obtaining a theory 

 of secretion, i.e. an. understanding of the additional forces besides osmotic 

 pressure which must be at work in the process of secretion. 



It is obvious from all these observations that the salts, especially 

 the Na-, K-, and Ca-salts, play a dominating r61e in the regulation of those 

 life phenomena which fall generally under the head of irritability or 

 stimulation and inhibition. To give a further idea of how far-reaching 

 the influence of salts in this direction is, I may mention the following 

 fact : Bock and Hoffmann * found, and other authors confirmed the fact, 

 that solutions of sodium salts, e.g. NaCl, NaBr, etc., when injected 

 into the blood, cause glycosuria in a rabbit. >It seemed to me that in 

 this case, too, the accelerating effect of citrates and the inhibiting effect 

 of Ca might be found. I asked Dr. M. H. Fischer, who was then a mem- 

 ber of the laboratory, to investigate this question. He found that it 

 is necessary in this case to infuse a NaCl solution of a higher concen- 



tration than -. The higher the concentration the quicker, according 

 o 



to Fischer, the glycosuria ensues. f Fischer found, also, that the citrates, 



etc., act more powerfully than NaCl, and that CaCl, was, to a certain 



extent, able to counteract this effect of NaCl. These observations 



support the idea of PfliigerJ that this is a case of nervous glycosuria 



produced , through the influence of the salts upon certain nervous 



elements in the medulla oblongata. It is possible that through this 



influence the concentration of sugar in the blood is raised transitorily, 



while the CaCl, has the opposite effect. MacCallum § has made the 



interesting observation that in this case sugar is secreted not only through 



the kidney but also into the intestine. 



If we finally summarize the results of these observations, we come 



to the conclusion that all those phenomena which depend on the action 



of muscles, nerves, or glands seem to be influenced to a large extent 



by the salts, and that especially changes in the proportion of Na or K 



to the Ca-ions in the tissues seem to affect their properties and their 



actions. The idea to which we have given preference, namely, that 



the substitution of Na or K for Ca, or vice versa, in certain organic 



compounds gives rise to a contraction, may possibly have to be modified 



in detail, and undoubtedly many new facts will be required and found 



before we are ready for a final theory ; but I am inclined to believe that 



the main structure will remain such as intimated in my papers in 1899 



* Bock und Hoffmann, Reichert und Du Bois-Reymond's Archiv, p. 550, 1871. 

 t Fischer, University of California Publications, Physiology, Vol. I, p. 77, 1903; p. 87, 

 1904. 



X Pfluger's Archiv, Vol. 96, p. 313, 1903. 



§ MacCallum, University of California Publications, Physiology, Vol. I, p. 125, 1904. 



